Photographic process



United States Patent 3,003,876 PHOTOGRAPHIC PROCESS Elkan R. Blout,Belmont, Saul G. Cohen, Lexington, and

Myron S. Simon, Newton Centre, Mass., assignors to Polaroid Corporation,Cambridge, Mass., a corporation of Delaware No Drawing. Filed Aug. 27,1957, Ser. No. 680,620

4 Claims. (Cl. 96-66) p This invention relates to chemistry and moreparticularly to novel chemical compounds and novel photographicprocesses utilizing said compounds as developing agents.

One object of this invention is to provide novel chemical compounds andsuitable syntheses for their prepara tion.

Another object of this invention is to provide novel chemical compoundsuseful as photographic developing agents and intermediates, and methodsof developing exposed photosensitive elements using said compounds.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps andlthe relationand order of one or more of such steps with respect to each of theothers, and the product possessing the features, properties and therelation of elements which are exemplified in the following detaileddisclosure, and the scope of the application of which will be indicatedin the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description. I

The novel compounds of this invention may be represented by the formula:

wherein each R when taken alone may be hydrogen, an alkyl and preferablya lower alkyl containing no more than 5 carbon atoms or an aryl group;the R s when taken together may be an ethylene or propylene group and assuch complete a 5 or 6 carbon cycloaliphatic ring; and each Y is anunsubstituted, alkyl-substituted, or halogen-substituted, ortho or paradihydroxyphenyl group; and the acid addition salts thereof. As examplesof suitable acid addition salts, mention may be made of thehydrohalides, e.g., hydrochloride or hydrobromide, and of organic acidsalts, such as the oxalates.

In a preferred embodiment, Y is a p-dihydroxyphenyl radical and suchcompounds may be represented by the formula:

wherein R is the same as above.

The preferred compound of this invention is 1,5-bis-(2',-dihydroxyphenyl) -3-pentylamine of the structure:

The novel compounds of this invention may be prepared by condensing asuitable dialkoxybenzaldehydewith a ketone of the structure R1CH2CCH2-R1I; wherein R has thesame meaning as above, hydrogenating the resultingunsaturated product, condensing the ketone with hydroxylamine to producethe oxime, converting the oxime to an amine by hydrogenation, andremoving the alkoxy groups by hydrolysis. In an alternate method, theketone condensation product may be converted directly to the amine byreductively aminating the keto group with ammonia and hydrogen.

The ketones used in preparing the novel compounds of' this inventionshould contain methyl or methylene radicals on both sides of the ketogroup and adjacent to the keto group, in order that the aldehydecondensation may proceed. As examples of ketones useful in preparing thenovel compounds of this invention, mention may be made of acetone,methyl-ethyl ketone, diethyl ketone, phenyl acetone, cyclopentanone andcyclohexanone.

As examples of suitable dialkoxybenzaldehydes, mention may be made of2,5-dimethoxybenzaldehyde and 3,4- dimethoxybenzaldehyde and their alkyland halogen substituted derivatives.

The following example illustrates the preparation ofl,S-bis-(2',5-dihydroxyphenyl)-3-pentylamine and is given for purposesof illustration only.

Example 1 Acetone (6.8 g.) and 2,5-dimethoxybenzaldehyde (39 g.) areadded to a vigorously stirred solution of sodium hydroxide (23.5 g.) ina mixture of water (235 cc.) and ethanol (190 cc.). The mixture isstirred at room temperature for about an hour after which a yellowsolidified oil'is filtered oif. Extraction with ether yields 1,5-bis-(2,5-dimethoxyphenyl)-penta-1,4-dien-3-one as yellow needles melting at108 to 108.5 C. This product, dis-- solved in ethyl acetate, ishydrogenated over Raney nickel, at room temperature and a pressure of 30p.s.i., to give 1,5-bis-(2',5'-dimethoxyphenyl)-3-pentanone as a whitecrystalline solid melting at C.

The oxime of the above ketone is prepared by refluxing the ketone withhydroxylamine in a 50:50 mixture, by volume, of pyridine and ethanol.After refluxing this mixture for two hours, it is evaporated to an oil,which is thoroughly washed with water. The product which crystallizesfrom this oil is recrystallized from ether to give a White crystallineproduct melting at to 87 C. Analysis of the oxime gives a nitrogen valueof 3.7% as compared with the calculated 3.75%.

The 1,5-bis-(2',5'-dimethoxyphenyl)-pentanone-3-oxime (40 g.) ishydrogenated in ethanol over Raney nickel at 120 C. and a hydrogenpressure of 1200-1300 psi. for one to one-and-one-half hours. Thehydrogenation product is filtered, the ethanol evaporated off and theresidue taken up in ether. Precipitation with hydrochloric acid gives a90% yield of the 1,5-bis-(2,5'-dimethoxyphenol)- 3-pentylaminehydrochloride as a white solid melting at 101 to 103 C.

The dimethoxy amine hydrochloride is refluxed under nitrogen for fivehours in concentrated hydrobromic acid, after which the reflux mixtureis evaporated to dryness at C. in vacuo. This product is washed severalPatented Oct. 10, 1961 invention are useful as photographic developingagents. As an example of a suitable developing compositionutilizing oneof the novel compounds of this invention, mention may be made of thefollowing composition:

Water cc 100 Potassium bromide gram 0.2 Sodium hydroxide grams 3.01,S-bis-(2,5'-dihydroxyphenyl)-3-pentylamine gram 1.0

It will be understood that it is within the scope of this invention tovary the above composition to suit particular needs. The percentage ofmaterials may be varied and additional materials useful in photographicprocesses may be added. If the composition is to be spread on a silverhalide emulsion, a film-forming thickening agent such, for example, assodium carboxymethyl cellulose, may be added.

The novel compounds of this invention are useful as developing agents indifiusion transfer processes, both dye and silver transfer, and areespecially useful in such photographic processes wherein it is desiredto eliminate or minimize the need for washing or stabilizing operationsin liquid baths subsequent to the formation of the silver print.Examples of such processes are disclosed in US. Patent No. 2,647,056 toEdwin H. Land. The utility of the developers of this invention is by nomeans limited. to difiusion transfer reversal processes for they may besatisfactorily employed in conventional multistage multibathphotographic processes in black-and-white or color photography. Wherethe herein disclosed compounds are employed in diffusion transferprocesses of the type disclosed in the aforementioned patent, the noveldeveloper composition may have incorporated therein as a furtheringredient a silver halide solvent such as sodium thiosulfate. Thus, byadding sodium thiosulfate to the composition illustrated above and usingan image-receiving element in conjunction with the photosensitiveelement, a silver transfer image may be obtained.

The novel compounds of this invention are again useful as intermediates.As an example of such use, mention may be made of the preparation of thedye developers claimed and disclosed in the copending application ofElkan R. Blout and Myron S. Simon, Serial No. 680,619,,

filed concurrently herewith, wherein the compounds of this invention areused in the syntheses of said dye developers.

The novel compounds of thisinvention are further useful as antioxidantsin petroleum products, etc.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that, all matter contained in the above description shall be,interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. A process for developing a photosensitive silver halide emulsionwhich comprises treating an exposedsilver halide emulsion with anaqueous alkaline solution of acompound represented by the formula:

References Cited in the file of this patent UNITED STATES PATENTS2,301,381 Dickey et a1. Nov. 10, 1942 2,541,889 Runyan Feb. 13, 19512,681,934 Hodge June 22, 1954 2,688,625 Bell et a1. Sept. 7, 19542,704,713 Bent et a1. Mar. 22, 1955 2,705,245 Norton Mar. 29, 19552,757,091 Oretzky July 31, 1956

1. A PROCESS FOR DEVELOPING A PHOTOSENSITIVE SILVER HALIDE EMULSIONWHICH COMPRISES TREATING AN EXPOSED SILVER HALIDE EMULSION WITH ANAQUEOUS ALKALINE SOLUTION OF A COMPOUND REPRESENTED BY THE FORMULA: